Overhead reduction for zone identifier transmission

ABSTRACT

Disclosed are techniques for wireless communication. In an aspect, a transmitter user equipment (UE) determines a first zone identifier (ID) corresponding to a first zone in which the transmitter UE is located, determines a distance threshold based on a distance requirement of an application associated with the transmitter UE, determines a second zone ID based on the first zone ID, the distance threshold, a size of the first zone, or any combination thereof, and transmits the second zone ID and the distance threshold to one or more receiver UEs. In an aspect, the receiver UE receives the second zone ID and the distance threshold, determines a distance between the receiver UE and the transmitter UE based on the second zone ID and a location of the receiver UE, and transmits, based on the distance being less than the distance threshold, a feedback message to the transmitter UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application for Patent is a divisional application of U.S.Pat. Application No. 16/904,240, entitled “OVERHEAD REDUCTION FOR ZONEIDENTIFIER TRANSMISSION,” filed Jun. 17, 2020, which claims the benefitof U.S. Provisional Application No. 62/893,631, entitled “OVERHEADREDUCTION FOR ZONE IDENTIFIER TRANSMISSION,” filed Aug. 29, 2019, eachof which is assigned to the assignee hereof, and expressly incorporatedherein by reference in its entirety.

BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure

Various aspects described herein generally relate to wirelesscommunication systems.

2. Description of the Related Art

Wireless communication systems have developed through variousgenerations, including a first-generation analog wireless phone service(1G), a second-generation (2G) digital wireless phone service (includinginterim 2.5G networks), a third-generation (3G) high speed data,Internet-capable wireless service and a fourth-generation (4G) service(e.g., LTE or WiMax). There are presently many different types ofwireless communication systems in use, including cellular and personalcommunications service (PCS) systems. Examples of known cellular systemsinclude the cellular analog advanced mobile phone system (AMPS), anddigital cellular systems based on code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), the global system for mobile access (GSM) variation of TDMA,etc.

A fifth generation (5G) wireless standard, referred to as New Radio(NR), enables higher data transfer speeds, greater numbers ofconnections, and better coverage, among other improvements. The NRstandard, according to the Next Generation Mobile Networks Alliance, isdesigned to provide data rates of several tens of megabits per second toeach of tens of thousands of users, with 1 gigabit per second to tens ofworkers on an office floor. Several hundreds of thousands ofsimultaneous connections should be supported in order to support largewireless sensor deployments. Consequently, the spectral efficiency of NRmobile communications should be significantly enhanced compared to thecurrent 4G standard. Furthermore, signaling efficiencies should beenhanced and latency should be substantially reduced compared to currentstandards.

Leveraging the increased data rates and decreased latency of 5G, amongother things, vehicle-to-everything (V2X) communication technologies arebeing implemented to support autonomous driving applications, such aswireless communications between vehicles, between vehicles and theroadside infrastructure, between vehicles and pedestrians, etc.

SUMMARY

This summary identifies features of some example aspects, and is not anexclusive or exhaustive description of the disclosed subject matter.Whether features or aspects are included in, or omitted from thissummary is not intended as indicative of relative importance of suchfeatures. Additional features and aspects are described, and will becomeapparent to persons skilled in the art upon reading the followingdetailed description and viewing the drawings that form a part thereof.

An aspect of the disclosure includes a method for wireless communicationperformed at a transmitter user equipment (UE), including: determining afirst zone identifier (ID) corresponding to a first zone in which thetransmitter UE is located; determining a distance threshold based on adistance requirement of an application associated with the transmitterUE; determining a second zone ID based on the first zone ID, thedistance threshold, a size of the first zone, or any combinationthereof; and transmitting the second zone ID and the distance thresholdto one or more receiver UEs.

An aspect of the disclosure includes a method for wireless communicationperformed at a receiver UE, including: receiving, from a transmitter UE,a second zone ID and a distance threshold; determining a location of thereceiver UE; determining a distance between the receiver UE and thetransmitter UE based on the second zone ID and the location of thereceiver UE; based on the distance between the receiver UE and thetransmitter UE being less than the distance threshold, transmitting afeedback message to the transmitter UE.

An aspect of the disclosure includes a transmitter UE, including: amemory; at least one transceiver; and at least one processorcommunicatively coupled to the memory and the at least one transceiver,the at least one processor configured to: determine a first zone IDcorresponding to a first zone in which the transmitter UE is located;determine a distance threshold based on a distance requirement of anapplication associated with the transmitter UE; determine a second zoneID based on the first zone ID, the distance threshold, a size of thefirst zone, or any combination thereof; and cause the at least onetransceiver to transmit the second zone ID and the distance threshold toone or more receiver UEs.

An aspect of the disclosure includes a receiver UE, including: a memory;at least one transceiver; and at least one processor communicativelycoupled to the memory and the at least one transceiver, the at least oneprocessor configured to: receive, from a transmitter UE via the at leastone transceiver, a second zone ID and a distance threshold; determine alocation of the receiver UE; determine a distance between the receiverUE and the transmitter UE based on the second zone ID and the locationof the receiver UE; and cause the at least one transceiver to transmit,based on the distance between the receiver UE and the transmitter UEbeing less than the distance threshold, a feedback message to thetransmitter UE.

An aspect of the disclosure includes a transmitter UE, including: meansfor determining a first zone ID corresponding to a first zone in whichthe transmitter UE is located; means for determining a distancethreshold based on a distance requirement of an application associatedwith the transmitter UE; means for determining a second zone ID based onthe first zone ID, the distance threshold, a size of the first zone, orany combination thereof; and means for transmitting the second zone IDand the distance threshold to one or more receiver UEs.

An aspect of the disclosure includes a receiver UE, including: means forreceiving, from a transmitter UE, a second zone ID and a distancethreshold; determining a location of the receiver UE; means fordetermining a distance between the receiver UE and the transmitter UEbased on the second zone ID and the location of the receiver UE; meansfor transmitting, based on the distance between the receiver UE and thetransmitter UE being less than the distance threshold, a feedbackmessage to the transmitter UE.

An aspect of the disclosure includes a non-transitory computer-readablemedium storing computer-executable instructions, the computer executableinstructions including: at least one instruction instructing atransmitter UE to determine a first zone ID corresponding to a firstzone in which the transmitter UE is located; at least one instructioninstructing the transmitter UE to determine a distance threshold basedon a distance requirement of an application associated with thetransmitter UE; at least one instruction instructing the transmitter UEto determine a second zone ID based on the first zone ID, the distancethreshold, a size of the first zone, or any combination thereof; and atleast one instruction instructing the transmitter UE to transmit thesecond zone ID and the distance threshold to one or more receiver UEs.

An aspect of the disclosure includes a non-transitory computer-readablemedium storing computer-executable instructions, the computer executableinstructions including: at least one instruction instructing a receiverUE to receive, from a transmitter UE, a second zone ID and a distancethreshold; at least one instruction instructing the receiver UE todetermine a location of the receiver UE; at least one instructioninstructing the receiver UE to determine a distance between the receiverUE and the transmitter UE based on the second zone ID and the locationof the receiver UE; at least one instruction instructing the receiver UEto transmit, based on the distance between the receiver UE and thetransmitter UE being less than the distance threshold, a feedbackmessage to the transmitter UE.

Other objects and advantages associated with the aspects disclosedherein will be apparent to those skilled in the art based on theaccompanying drawings and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are presented to aid in the description ofexamples of one or more aspects of the disclosed subject matter and areprovided solely for illustration of the examples and not limitationthereof:

FIG. 1 illustrates an exemplary wireless communications system inaccordance with one or more aspects of the disclosure.

FIGS. 2A and 2B illustrate example wireless network structures,according to various aspects.

FIG. 3 illustrates an example of a wireless communications system thatsupports unicast sidelink establishment in accordance with aspects ofthe disclosure.

FIG. 4 is a block diagram illustrating various components of anexemplary UE according to at least one aspect of the disclosure.

FIG. 5 is a diagram of an exemplary wraparound scenario, according toaspects of the disclosure.

FIG. 6 is a diagram of a 16-by-16 zone area in which groups of fourzones are combined into a zone group and assigned a second zone ID,according to aspects of the disclosure.

FIG. 7 illustrates how to determine the bits of a second zone ID fromthe bits of a first zone ID, according to aspects of the disclosure.

FIGS. 8 to 10 illustrate exemplary methods for wireless communication,according to aspects of the disclosure.

DETAILED DESCRIPTION

Aspects of the disclosure are provided in the following description andrelated drawings directed to various examples provided for illustrationpurposes. Alternate aspects may be devised without departing from thescope of the disclosure. Additionally, well-known elements of thedisclosure will not be described in detail or will be omitted so as notto obscure the relevant details of the disclosure.

The words “exemplary” and/or “example” are used herein to mean “servingas an example, instance, or illustration.” Any aspect described hereinas “exemplary” and/or “example” is not necessarily to be construed aspreferred or advantageous over other aspects. Likewise, the term“aspects of the disclosure” does not require that all aspects of thedisclosure include the discussed feature, advantage or mode ofoperation.

Those of skill in the art will appreciate that the information andsignals described below may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the description below may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, or any combination thereof, depending inpart on the particular application, in part on the desired design, inpart on the corresponding technology, etc.

Further, many aspects are described in terms of sequences of actions tobe performed by, for example, elements of a computing device. It will berecognized that various actions described herein can be performed byspecific circuits (e.g., application specific integrated circuits(ASICs)), by program instructions being executed by one or moreprocessors, or by a combination of both. Additionally, the sequence(s)of actions described herein can be considered to be embodied entirelywithin any form of non-transitory computer-readable storage mediumhaving stored therein a corresponding set of computer instructions that,upon execution, would cause or instruct an associated processor of adevice to perform the functionality described herein. Thus, the variousaspects of the disclosure may be embodied in a number of differentforms, all of which have been contemplated to be within the scope of theclaimed subject matter. In addition, for each of the aspects describedherein, the corresponding form of any such aspects may be describedherein as, for example, “logic configured to” perform the describedaction.

As used herein, the terms “user equipment” (UE), “vehicle UE” (V-UE),“pedestrian UE” (P-UE), and “base station” are not intended to bespecific or otherwise limited to any particular radio access technology(RAT), unless otherwise noted. In general, a UE may be any wirelesscommunication device (e.g., vehicle on-board computer, vehiclenavigation device, mobile phone, router, tablet computer, laptopcomputer, tracking device, wearable (e.g., smartwatch, glasses,augmented reality (AR) / virtual reality (VR) headset, etc.), vehicle(e.g., automobile, motorcycle, bicycle, etc.), Internet of Things (IoT)device, etc.) used by a user to communicate over a wirelesscommunications network. A UE may be mobile or may (e.g., at certaintimes) be stationary, and may communicate with a radio access network(RAN). As used herein, the term “UE” may be referred to interchangeablyas an “access terminal” or “AT,” a “client device,” a “wireless device,”a “subscriber device,” a “subscriber terminal,” a “subscriber station,”a “user terminal” or UT, a “mobile terminal,” a “mobile station,” orvariations thereof.

A V-UE is a type of UE and may be any in-vehicle wireless communicationdevice, such as a navigation system, a warning system, a heads-updisplay (HUD), an on-board computer, etc. Alternatively, a V-UE may be aportable wireless communication device (e.g., a cell phone, tabletcomputer, etc.) that is carried by the driver of the vehicle or apassenger in the vehicle. The term “V-UE” may refer to the in-vehiclewireless communication device or the vehicle itself, depending on thecontext. A P-UE is a type of UE and may be a portable wirelesscommunication device that is carried by a pedestrian (i.e., a user thatis not driving or riding in a vehicle). Generally, UEs can communicatewith a core network via a RAN, and through the core network the UEs canbe connected with external networks such as the Internet and with otherUEs. Of course, other mechanisms of connecting to the core networkand/or the Internet are also possible for the UEs, such as over wiredaccess networks, wireless local area network (WLAN) networks (e.g.,based on IEEE 802.11, etc.) and so on.

A base station may operate according to one of several RATs incommunication with UEs depending on the network in which it is deployed,and may be alternatively referred to as an access point (AP), a networknode, a NodeB, an evolved NodeB (eNB), a New Radio (NR) Node B (alsoreferred to as a gNB or gNodeB), etc. In addition, in some systems abase station may provide purely edge node signaling functions while inother systems it may provide additional control and/or networkmanagement functions. A communication link through which UEs can sendsignals to a base station is called an uplink (UL) channel (e.g., areverse traffic channel, a reverse control channel, an access channel,etc.). A communication link through which the base station can sendsignals to UEs is called a downlink (DL) or forward link channel (e.g.,a paging channel, a control channel, a broadcast channel, a forwardtraffic channel, etc.). As used herein the term traffic channel (TCH)can refer to either an UL / reverse or DL / forward traffic channel.

The term “base station” may refer to a single physicaltransmission-reception point (TRP) or to multiple physical TRPs that mayor may not be co-located. For example, where the term “base station”refers to a single physical TRP, the physical TRP may be an antenna ofthe base station corresponding to a cell of the base station. Where theterm “base station” refers to multiple co-located physical TRPs, thephysical TRPs may be an array of antennas (e.g., as in a multiple-inputmultiple-output (MIMO) system or where the base station employsbeamforming) of the base station. Where the term “base station” refersto multiple non-co-located physical TRPs, the physical TRPs may be adistributed antenna system (DAS) (a network of spatially separatedantennas connected to a common source via a transport medium) or aremote radio head (RRH) (a remote base station connected to a servingbase station). Alternatively, the non-co-located physical TRPs may bethe serving base station receiving the measurement report from the UEand a neighbor base station whose reference RF signals the UE ismeasuring. Because a TRP is the point from which a base stationtransmits and receives wireless signals, as used herein, references totransmission from or reception at a base station are to be understood asreferring to a particular TRP of the base station.

An “RF signal” comprises an electromagnetic wave of a given frequencythat transports information through the space between a transmitter anda receiver. As used herein, a transmitter may transmit a single “RFsignal” or multiple “RF signals” to a receiver. However, the receivermay receive multiple “RF signals” corresponding to each transmitted RFsignal due to the propagation characteristics of RF signals throughmultipath channels. The same transmitted RF signal on different pathsbetween the transmitter and receiver may be referred to as a “multipath”RF signal.

According to various aspects, FIG. 1 illustrates an exemplary wirelesscommunications system 100. The wireless communications system 100 (whichmay also be referred to as a wireless wide area network (WWAN)) mayinclude various base stations 102 (labelled “BS”) and various UEs 104.The base stations 102 may include macro cell base stations (high powercellular base stations) and/or small cell base stations (low powercellular base stations). In an aspect, the macro cell base stations 102may include eNBs where the wireless communications system 100corresponds to an LTE network, or gNBs where the wireless communicationssystem 100 corresponds to a NR network, or a combination of both, andthe small cell base stations may include femtocells, picocells,microcells, etc.

The base stations 102 may collectively form a RAN and interface with acore network 174 (e.g., an evolved packet core (EPC) or next generationcore (NGC)) through backhaul links 122, and through the core network 174to one or more location servers 172. In addition to other functions, thebase stations 102 may perform functions that relate to one or more oftransferring user data, radio channel ciphering and deciphering,integrity protection, header compression, mobility control functions(e.g., handover, dual connectivity), inter-cell interferencecoordination, connection setup and release, load balancing, distributionfor non-access stratum (NAS) messages, NAS node selection,synchronization, RAN sharing, multimedia broadcast multicast service(MBMS), subscriber and equipment trace, RAN information management(RIM), paging, positioning, and delivery of warning messages. The basestations 102 may communicate with each other directly or indirectly(e.g., through the EPC / NGC) over backhaul links 134, which may bewired or wireless.

The base stations 102 may wirelessly communicate with the UEs 104. Eachof the base stations 102 may provide communication coverage for arespective geographic coverage area 110. In an aspect, one or more cellsmay be supported by a base station 102 in each geographic coverage area110. A “cell” is a logical communication entity used for communicationwith a base station (e.g., over some frequency resource, referred to asa carrier frequency, component carrier, carrier, band, or the like), andmay be associated with an identifier (e.g., a physical cell identifier(PCI), an enhanced cell identifier (ECI), a virtual cell identifier(VCI), etc.) for distinguishing cells operating via the same or adifferent carrier frequency. In some cases, different cells may beconfigured according to different protocol types (e.g., machine-typecommunication (MTC), narrowband IoT (NB-IoT), enhanced mobile broadband(eMBB), or others) that may provide access for different types of UEs.Because a cell is supported by a specific base station, the term “cell”may refer to either or both the logical communication entity and thebase station that supports it, depending on the context. In some cases,the term “cell” may also refer to a geographic coverage area of a basestation (e.g., a sector), insofar as a carrier frequency can be detectedand used for communication within some portion of geographic coverageareas 110.

While neighboring macro cell base station 102 geographic coverage areas110 may partially overlap (e.g., in a handover region), some of thegeographic coverage areas 110 may be substantially overlapped by alarger geographic coverage area 110. For example, a small cell basestation 102′ (labelled “SC” for “small cell”) may have a geographiccoverage area 110′ that substantially overlaps with the geographiccoverage area 110 of one or more macro cell base stations 102. A networkthat includes both small cell and macro cell base stations may be knownas a heterogeneous network. A heterogeneous network may also includehome eNBs (HeNBs), which may provide service to a restricted group knownas a closed subscriber group (CSG).

The communication links 120 between the base stations 102 and the UEs104 may include UL (also referred to as reverse link) transmissions froma UE 104 to a base station 102 and/or downlink (DL) (also referred to asforward link) transmissions from a base station 102 to a UE 104. Thecommunication links 120 may use MIMO antenna technology, includingspatial multiplexing, beamforming, and/or transmit diversity. Thecommunication links 120 may be through one or more carrier frequencies.Allocation of carriers may be asymmetric with respect to DL and UL(e.g., more or less carriers may be allocated for DL than for UL).

The wireless communications system 100 may further include a wirelesslocal area network (WLAN) access point (AP) 150 in communication withWLAN stations (STAs) 152 via communication links 154 in an unlicensedfrequency spectrum (e.g., 5 GHz). When communicating in an unlicensedfrequency spectrum, the WLAN STAs 152 and/or the WLAN AP 150 may performa clear channel assessment (CCA) or listen before talk (LBT) procedureprior to communicating in order to determine whether the channel isavailable.

The small cell base station 102′ may operate in a licensed and/or anunlicensed frequency spectrum. When operating in an unlicensed frequencyspectrum, the small cell base station 102′ may employ LTE or NRtechnology and use the same 5 GHz unlicensed frequency spectrum as usedby the WLAN AP 150. The small cell base station 102′, employing LTE / 5Gin an unlicensed frequency spectrum, may boost coverage to and/orincrease capacity of the access network. NR in unlicensed spectrum maybe referred to as NR-U. LTE in an unlicensed spectrum may be referred toas LTE-U, licensed assisted access (LAA), or MulteFire.

The wireless communications system 100 may further include a millimeterwave (mmW) base station 180 that may operate in mmW frequencies and/ornear mmW frequencies in communication with a UE 182. Extremely highfrequency (EHF) is part of the RF in the electromagnetic spectrum. EHFhas a range of 30 GHz to 300 GHz and a wavelength between 1 millimeterand 10 millimeters. Radio waves in this band may be referred to as amillimeter wave. Near mmW may extend down to a frequency of 3 GHz with awavelength of 100 millimeters. The super high frequency (SHF) bandextends between 3 GHz and 30 GHz, also referred to as centimeter wave.Communications using the mmW/near mmW radio frequency band have highpath loss and a relatively short range. The mmW base station 180 and theUE 182 may utilize beamforming (transmit and/or receive) over a mmWcommunication link 184 to compensate for the extremely high path lossand short range. Further, it will be appreciated that in alternativeconfigurations, one or more base stations 102 may also transmit usingmmW or near mmW and beamforming. Accordingly, it will be appreciatedthat the foregoing illustrations are merely examples and should not beconstrued to limit the various aspects disclosed herein.

Transmit beamforming is a technique for focusing an RF signal in aspecific direction. Traditionally, when a network node (e.g., a basestation) broadcasts an RF signal, it broadcasts the signal in alldirections (omni-directionally). With transmit beamforming, the networknode determines where a given target device (e.g., a UE) is located(relative to the transmitting network node) and projects a strongerdownlink RF signal in that specific direction, thereby providing afaster (in terms of data rate) and stronger RF signal for the receivingdevice(s). To change the directionality of the RF signal whentransmitting, a network node can control the phase and relativeamplitude of the RF signal at each of the one or more transmitters thatare broadcasting the RF signal. For example, a network node may use anarray of antennas (referred to as a “phased array” or an “antennaarray”) that creates a beam of RF waves that can be “steered” to pointin different directions, without actually moving the antennas.Specifically, the RF current from the transmitter is fed to theindividual antennas with the correct phase relationship so that theradio waves from the separate antennas add together to increase theradiation in a desired direction, while cancelling to suppress radiationin undesired directions.

Transmit beams may be quasi-collocated, meaning that they appear to thereceiver (e.g., a UE) as having the same parameters, regardless ofwhether or not the transmitting antennas of the network node themselvesare physically collocated. In NR, there are four types ofquasi-collocation (QCL) relations. Specifically, a QCL relation of agiven type means that certain parameters about a second reference RFsignal on a second beam can be derived from information about a sourcereference RF signal on a source beam. Thus, if the source reference RFsignal is QCL Type A, the receiver can use the source reference RFsignal to estimate the Doppler shift, Doppler spread, average delay, anddelay spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type B, the receivercan use the source reference RF signal to estimate the Doppler shift andDoppler spread of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type C, the receivercan use the source reference RF signal to estimate the Doppler shift andaverage delay of a second reference RF signal transmitted on the samechannel. If the source reference RF signal is QCL Type D, the receivercan use the source reference RF signal to estimate the spatial receiveparameter of a second reference RF signal transmitted on the samechannel.

In receive beamforming, the receiver uses a receive beam to amplify RFsignals detected on a given channel. For example, the receiver canincrease the gain setting and/or adjust the phase setting of an array ofantennas in a particular direction to amplify (e.g., to increase thegain level of) the RF signals received from that direction. Thus, when areceiver is said to beamform in a certain direction, it means the beamgain in that direction is high relative to the beam gain along otherdirections, or the beam gain in that direction is the highest comparedto the beam gain in that direction of all other receive beams availableto the receiver. This results in a stronger received signal strength(e.g., reference signal received power (RSRP), reference signal receivedquality (RSRQ), signal-to-interference-plus-noise ratio (SINR), etc.) ofthe RF signals received from that direction.

Transmit and receive beams may be spatially related. A spatial relationmeans that parameters for a second beam (e.g., a transmit or receivebeam) for a second reference signal can be derived from informationabout a first beam (e.g., a receive beam or a transmit beam) for a firstreference signal. For example, a UE may use a particular receive beam toreceive a reference downlink reference signal (e.g., synchronizationsignal block (SSB)) from a base station. The UE can then form a transmitbeam for sending an uplink reference signal (e.g., sounding referencesignal (SRS)) to that base station based on the parameters of thereceive beam.

Note that a “downlink” beam may be either a transmit beam or a receivebeam, depending on the entity forming it. For example, if a base stationis forming the downlink beam to transmit a reference signal to a UE, thedownlink beam is a transmit beam. If the UE is forming the downlinkbeam, however, it is a receive beam to receive the downlink referencesignal. Similarly, an “uplink” beam may be either a transmit beam or areceive beam, depending on the entity forming it. For example, if a basestation is forming the uplink beam, it is an uplink receive beam, and ifa UE is forming the uplink beam, it is an uplink transmit beam.

In 5G, the frequency spectrum in which wireless nodes (e.g., basestations 102/180, UEs 104/182) operate is divided into multiplefrequency ranges, FR1 (from 450 to 6000 MHz), FR2 (from 24250 to 52600MHz), FR3 (above 52600 MHz), and FR4 (between FR1 and FR2). In amulti-carrier system, such as 5G, one of the carrier frequencies isreferred to as the “primary carrier” or “anchor carrier” or “primaryserving cell” or “PCell,” and the remaining carrier frequencies arereferred to as “secondary carriers” or “secondary serving cells” or“SCells.” In carrier aggregation, the anchor carrier is the carrieroperating on the primary frequency (e.g., FR1) utilized by a UE 104/182and the cell in which the UE 104/182 either performs the initial radioresource control (RRC) connection establishment procedure or initiatesthe RRC connection re-establishment procedure. The primary carriercarries all common and UE-specific control channels, and may be acarrier in a licensed frequency (however, this is not always the case).A secondary carrier is a carrier operating on a second frequency (e.g.,FR2) that may be configured once the RRC connection is establishedbetween the UE 104 and the anchor carrier and that may be used toprovide additional radio resources. In some cases, the secondary carriermay be a carrier in an unlicensed frequency. The secondary carrier,while containing necessary signaling information and signals, may notinclude UE-specific information in the secondary carrier, since bothprimary uplink and downlink carriers are typically UE-specific. Thismeans that different UEs 104/182 in a cell may have different downlinkprimary carriers. The same is true for the uplink primary carriers. Thenetwork is able to change the primary carrier of any UE 104/182 at anytime. This is done, for example, to balance the load on differentcarriers. Because a “serving cell” (whether a PCell or an SCell)corresponds to a carrier frequency / component carrier over which somebase station is communicating, the term “cell,” “serving cell,”“component carrier,” “carrier frequency,” and the like can be usedinterchangeably.

For example, still referring to FIG. 1 , one of the frequencies utilizedby the macro cell base stations 102 may be an anchor carrier (or“PCell”) and other frequencies utilized by the macro cell base stations102 and/or the mmW base station 180 may be secondary carriers(“SCells”). The simultaneous transmission and/or reception of multiplecarriers enables the UE 104/182 to significantly increase its datatransmission and/or reception rates. For example, two 20 MHz aggregatedcarriers in a multi-carrier system would theoretically lead to atwo-fold increase in data rate (i.e., 40 MHz), compared to that attainedby a single 20 MHz carrier.

The wireless communications system 100 may further include one or moreUEs, such as UE 190, that connects indirectly to one or morecommunication networks via one or more device-to-device (D2D)peer-to-peer (P2P) links. In the example of FIG. 1 , UE 190 has a D2DP2P link 192 with one of the UEs 104 connected to one of the basestations 102 (e.g., through which UE 190 may indirectly obtain cellularconnectivity) and a D2D P2P link 194 with WLAN STA 152 connected to theWLAN AP 150 (through which UE 190 may indirectly obtain WLAN-basedInternet connectivity). In an example, the D2D P2P links 192 and 194 maybe supported with any well-known D2D RAT, such as LTE Direct (LTE-D),WiFi Direct (WiFi-D), Bluetooth®, and so on.

Leveraging the increased data rates and decreased latency of NR, amongother things, vehicle-to-everything (V2X) communication technologies arebeing implemented to support intelligent transportation systems (ITS)applications, such as wireless communications between vehicles(vehicle-to-vehicle (V2V)), between vehicles and the roadsideinfrastructure (vehicle-to-infrastructure (V2I)), and between vehiclesand pedestrians (vehicle-to-pedestrian (V2P)). The goal is for vehiclesto be able to sense the environment around them and communicate thatinformation to other vehicles, infrastructure, and personal mobiledevices. Such vehicle communication will enable safety, mobility, andenvironmental advancements that current technologies are unable toprovide. Once fully implemented, the technology is expected to reduceunimpaired vehicle crashes by 80%.

Still referring to FIG. 1 , the wireless communications system 100 mayinclude multiple V-UEs 160 that may communicate with base stations 102over communication links 120 (e.g., using the Uu interface). V-UEs 160may also communicate directly with each other over a wireless unicastsidelink 162, with a roadside access point 164 over a sidelink 166, orwith UEs 104 over a sidelink 168 using P2P/D2D protocols (e.g., “PC5,”an LTE V2X D2D interface) or ProSe direct communications. Sidelinkcommunication may be used for D2D media-sharing, V2V communication, V2Xcommunication (e.g., cellular V2X (cV2X) communication, enhanced V2X(eV2X) communication, etc.), emergency rescue applications, etc. One ormore of a group of V-UEs 160 utilizing D2D communications may be withinthe geographic coverage area 110 of a base station 102. Other V-UEs 160in such a group may be outside the geographic coverage area 110 of abase station 102 or be otherwise unable to receive transmissions from abase station 102. In some cases, groups of V-UEs 160 communicating viaD2D communications may utilize a one-to-many (1:M) system in which eachV-UE 160 transmits to every other V-UE 160 in the group. In some cases,a base station 102 facilitates the scheduling of resources for D2Dcommunications. In other cases, D2D communications are carried outbetween V-UEs 160 without the involvement of a base station 102.

In an aspect, the V-UEs 160, and any other UE illustrated in FIG. 1 ,may have a zone location component 170. The zone location component 170may be a hardware, software, or firmware component that, when executed,causes the V-UE 160 to perform the operations described herein. Forexample, the zone location component 170 may be a software module storedin a memory of the V-UE 160 and executable by a processor of the V-UE160. As another example, the zone location component 170 may be ahardware circuit (e.g., an ASIC, a field programmable gate array (FPGA),etc.) within the V-UE 160.

In an aspect, the sidelinks 162, 166, 168 may operate over acommunication medium of interest, which may be shared with othercommunications between other vehicles and/or infrastructure accesspoints, as well as other RATs. A “medium” may be composed of one or morefrequency, time, and/or space communication resources (e.g.,encompassing one or more channels across one or more carriers)associated with communication between one or more transmitter / receiverpairs.

In an aspect, the sidelinks 162, 166, 168 may be cV2X links. A firstgeneration of cV2X has been standardized in LTE, and the next generationis expected to be defined in NR. cV2X is a cellular technology that alsoenables device-to-device communications. In the U.S. and Europe, cV2X isexpected to operate in the licensed ITS band in sub-6GHz. Other bandsmay be allocated in other countries. Thus, as a particular example, themedium of interest utilized by sidelinks 162, 166, 168 may correspond toat least a portion of the licensed ITS frequency band of sub-6GHz.However, the present disclosure is not limited to this frequency band orcellular technology.

In an aspect, the sidelinks 162, 166, 168 may be dedicated short-rangecommunications (DSRC) links. DSRC is a one-way or two-way short-range tomedium-range wireless communication protocol that uses the wirelessaccess for vehicular environments (WAVE) protocol, also known as IEEE802.11p, for V2V, V2I, and V2P communications. IEEE 802.11p is anapproved amendment to the IEEE 802.11 standard and operates in thelicensed ITS band of 5.9 GHz (5.85-5.925 GHz) in the U.S. In Europe,IEEE 802.11p operates in the ITS G5A band (5.875 - 5.905 MHz). Otherbands may be allocated in other countries. The V2V communicationsbriefly described above occur on the Safety Channel, which in the U.S.is typically a 10 MHz channel that is dedicated to the purpose ofsafety. The remainder of the DSRC band (the total bandwidth is 75 MHz)is intended for other services of interest to drivers, such as roadrules, tolling, parking automation, etc. Thus, as a particular example,the mediums of interest utilized by sidelinks 162, 166, 168 maycorrespond to at least a portion of the licensed ITS frequency band of5.9 GHz.

Alternatively, the medium of interest may correspond to at least aportion of an unlicensed frequency band shared among various RATs.Although different licensed frequency bands have been reserved forcertain communication systems (e.g., by a government entity such as theFederal Communications Commission (FCC) in the United States), thesesystems, in particular those employing small cell access points, haverecently extended operation into unlicensed frequency bands such as theUnlicensed National Information Infrastructure (U-NII) band used bywireless local area network (WLAN) technologies, most notably IEEE802.11x WLAN technologies generally referred to as “Wi-Fi.” Examplesystems of this type include different variants of CDMA systems, TDMAsystems, FDMA systems, orthogonal FDMA (OFDMA) systems, single-carrierFDMA (SC-FDMA) systems, and so on.

Communications between the V-UEs 160 are referred to as V2Vcommunications, communications between the V-UEs 160 and the one or moreroadside access points 164 are referred to as V2I communications, andcommunications between the V-UEs 160 and one or more UEs 104 (where theUEs 104 are P-UEs) are referred to as V2P communications. The V2Vcommunications between V-UEs 160 may include, for example, informationabout the position, speed, acceleration, heading, and other vehicle dataof the V-UEs 160. The V2I information received at a V-UE 160 from theone or more roadside access points 164 may include, for example, roadrules, parking automation information, etc. The V2P communicationsbetween a V-UE 160 and a UE 104 may include information about, forexample, the position, speed, acceleration, and heading of the V-UE 160and the position, speed (e.g., where the UE 104 is carried by a user ona bicycle), and heading of the UE 104.

Note that although FIG. 1 illustrates two of the UEs as V-UEs (V-UEs160), any of the illustrated UEs (e.g., UEs 104, 152, 182, 190) may beV-UEs. In addition, although UE 182 was described as being capable ofbeam forming, any of the illustrated UEs, including V-UEs 160, may becapable of beam forming. Where V-UEs 160 are capable of beam forming,they may beam form towards each other (i.e., towards other V-UEs 160),towards roadside access points 164, towards other UEs (e.g., UEs 104,152, 182, 190), etc. Thus, in some cases, V-UEs 160 may utilizebeamforming over sidelinks 162, 166, and 168.

According to various aspects, FIG. 2A illustrates an exemplary wirelessnetwork structure 200. For example, an NGC 210 (also referred to as a“5GC”) can be viewed functionally as control plane functions (C-plane)214 (e.g., UE registration, authentication, network access, gatewayselection, etc.) and user plane functions (U-plane) 212 (e.g., UEgateway function, access to data networks, IP routing, etc.), whichoperate cooperatively to form the core network. User plane interface(NG-U) 213 and control plane interface (NG-C) 215 connect the gNB 222 tothe NGC 210 and specifically to the user plane functions 212 and controlplane functions 214, respectively. In an additional configuration, aneNB 224 may also be connected to the NGC 210 via NG-C 215 to the controlplane functions 214 and NG-U 213 to user plane functions 212. Further,eNB 224 may directly communicate with gNB 222 via a backhaul connection223. In some configurations, the New RAN 220 may have one or more gNBs222 but no eNBs 224, while other configurations may include one or moreof both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 may communicatewith UEs 204 (e.g., any of the UEs depicted in FIG. 1 ). In an aspect,two UEs 204 may communicate with each other over a wireless unicastsidelink 242, which may correspond to wireless unicast sidelink 162 inFIG. 1 .

Another optional aspect may include location server 230, which may be incommunication with the NGC 210 to provide location assistance for UEs204. The location server 230 can be implemented as a plurality ofseparate servers (e.g., physically separate servers, different softwaremodules on a single server, different software modules spread acrossmultiple physical servers, etc.), or alternately may each correspond toa single server. The location server 230 can be configured to supportone or more location services for UEs 204 that can connect to thelocation server 230 via the core network, NGC 210, and/or via theInternet (not illustrated). Further, the location server 230 may beintegrated into a component of the core network, or alternatively may beexternal to the core network.

According to various aspects, FIG. 2B illustrates another exemplarywireless network structure 250. For example, an NGC 260 (also referredto as a “5GC”) can be viewed functionally as control plane functions,provided by an access and mobility management function (AMF) / userplane function (UPF) 264, and user plane functions, provided by asession management function (SMF) 262, which operate cooperatively toform the core network (i.e., NGC 260). User plane interface 263 andcontrol plane interface 265 connect the eNB 224 to the NGC 260 andspecifically to SMF 262 and AMF/UPF 264, respectively. In an additionalconfiguration, a gNB 222 may also be connected to the NGC 260 viacontrol plane interface 265 to AMF/UPF 264 and user plane interface 263to SMF 262. Further, eNB 224 may directly communicate with gNB 222 viathe backhaul connection 223, with or without gNB direct connectivity tothe NGC 260. In some configurations, the New RAN 220 may have one ormore gNBs 222 and no eNBs 224, while other configurations may includeone or more of both eNBs 224 and gNBs 222. Either gNB 222 or eNB 224 maycommunicate with UEs 204 (e.g., any of the UEs depicted in FIG. 1 ). Thebase stations of the New RAN 220 communicate with the AMF-side of theAMF/UPF 264 over the N2 interface and the UPF-side of the AMF/UPF 264over the N3 interface. In an aspect, two UEs 204 may communicate witheach other over a wireless unicast sidelink 242, which may correspond towireless unicast sidelink 162 in FIG. 1 .

The functions of the AMF include registration management, connectionmanagement, reachability management, mobility management, lawfulinterception, transport for session management (SM) messages between theUE 204 and the SMF 262, transparent proxy services for routing SMmessages, access authentication and access authorization, transport forshort message service (SMS) messages between the UE 204 and the shortmessage service function (SMSF) (not shown), and security anchorfunctionality (SEAF). The AMF also interacts with the authenticationserver function (AUSF) (not shown) and the UE 204, and receives theintermediate key that was established as a result of the UE 204authentication process. In the case of authentication based on a UMTS(universal mobile telecommunications system) subscriber identity module(USIM), the AMF retrieves the security material from the AUSF. Thefunctions of the AMF also include security context management (SCM). TheSCM receives a key from the SEAF that it uses to derive access-networkspecific keys. The functionality of the AMF also includes locationservices management for regulatory services, transport for locationservices messages between the UE 204 and the location managementfunction (LMF) 270, as well as between the New RAN 220 and the LMF 270,evolved packet system (EPS) bearer identifier allocation forinterworking with the EPS, and UE 204 mobility event notification. Inaddition, the AMF also supports functionalities for non-3GPP accessnetworks.

Functions of the UPF include acting as an anchor point forintra-/inter-RAT mobility (when applicable), acting as an externalprotocol data unit (PDU) session point of interconnect to the datanetwork (not shown), providing packet routing and forwarding, packetinspection, user plane policy rule enforcement (e.g., gating,redirection, traffic steering), lawful interception (user planecollection), traffic usage reporting, quality of service (QoS) handlingfor the user plane (e.g., uplink/downlink rate enforcement, reflectiveQoS marking in the downlink), uplink traffic verification (service dataflow (SDF) to QoS flow mapping), transport level packet marking in theuplink and downlink, downlink packet buffering and downlink datanotification triggering, and sending and forwarding of one or more “endmarkers” to the source RAN node.

The functions of the SMF 262 include session management, UE Internetprotocol (IP) address allocation and management, selection and controlof user plane functions, configuration of traffic steering at the UPF toroute traffic to the proper destination, control of part of policyenforcement and QoS, and downlink data notification. The interface overwhich the SMF 262 communicates with the AMF-side of the AMF/UPF 264 isreferred to as the N11 interface.

Another optional aspect may include a LMF 270, which may be incommunication with the NGC 260 to provide location assistance for UEs204. The LMF 270 can be implemented as a plurality of separate servers(e.g., physically separate servers, different software modules on asingle server, different software modules spread across multiplephysical servers, etc.), or alternately may each correspond to a singleserver. The LMF 270 can be configured to support one or more locationservices for UEs 204 that can connect to the LMF 270 via the corenetwork, NGC 260, and/or via the Internet (not illustrated).

FIG. 3 illustrates an example of a wireless communications system 300that supports unicast sidelink establishment in accordance with aspectsof the disclosure. In some examples, wireless communications system 300may implement aspects of wireless communications systems 100, 200, and250. Wireless communications system 300 may include a first UE 302 and asecond UE 304, which may be examples of any of the UEs described herein.As a specific example, UEs 302 and 304 may correspond to V-UEs 160 inFIG. 1 . In the example of FIG. 3 , the UE 302 may attempt to establisha unicast connection over a sidelink with UE 304, which may be a V2Xcommunication link between UE 302 and UE 304. Additionally oralternatively, the unicast connection over the sidelink may generally beused for sidelink communications between any two UEs. Thus, theestablished sidelink connection may correspond to sidelinks 162 and/or168 in FIG. 1 and/or wireless unicast sidelink 242 in FIGS. 2A and 2B.In some cases, UE 302 may be referred to as an initiating UE thatinitiates the unicast connection procedure, and UE 304 may be referredto as a target UE that is targeted for the unicast connection procedureby the initiating UE.

For establishing the unicast connection, access stratum (AS) (afunctional layer in the UMTS and LTE protocol stacks between the RAN andthe UE that is responsible for transporting data over wireless links andmanaging radio resources, also referred to as “Layer 2” or “L2”)parameters may be configured and negotiated between UE 302 and UE 304.For example, a transmission and reception capability matching may benegotiated between UE 302 and UE 304. Each UE may have differentcapabilities (e.g., transmission and reception capabilities, 64quadrature amplitude modulation (QAM), transmission diversity, carrieraggregation (CA) capabilities, supported communications frequencyband(s), etc.). In some cases, different services may be supported atthe upper layers of corresponding protocol stacks for UE 302 and UE 304.Additionally, a security association may be established between UE 302and UE 304 for the unicast connection. Unicast traffic may benefit fromsecurity protection at a link level (e.g., integrity protection).Security requirements may differ for different wireless communicationssystems. For example, V2X and Uu systems may have different securityrequirements (e.g., Uu security does not include confidentialityprotection). Additionally, IP configurations (e.g., IP versions,addresses, etc.) may be negotiated for the unicast connection between UE302 and UE 304.

In some cases, UE 304 may create a service announcement (e.g., a servicecapability message) to transmit over a cellular network (e.g., cV2X) toassist the unicast connection establishment. Conventionally, UE 302 mayidentify and locate candidates for unicast communications based on abasic service message (BSM) broadcasted unencrypted by nearby UEs (e.g.,UE 304). The BSM may include location information, security and identityinformation, and vehicle information (e.g., speed, maneuver, size, etc.)for the corresponding UE. However, for different wireless communicationssystems (e.g., D2D or V2X communications), a discovery channel may notbe configured so that UE 302 is able to detect the BSM(s). Accordingly,the service announcement transmitted by UE 304 and other nearby UEs(e.g., a discovery signal) may be an upper layer signal and broadcasted(e.g., in a NR sidelink broadcast). In some cases, UE 304 may includeone or more parameters for itself in the service announcement, includingconnection parameters and/or capabilities it possesses. UE 302 may thenmonitor for and receive the broadcasted service announcement to identifypotential UEs for corresponding unicast connections. In some cases, UE302 may identify the potential UEs based on the capabilities each UEindicates in their respective service announcements.

The service announcement may include information to assist UE 302 (e.g.,or any initiating UE) to identify the UE transmitting the serviceannouncement (UE 304 in the example of FIG. 3 ). For example, theservice announcement may include channel information where directcommunication requests may be sent. In some cases, the channelinformation may be specific to RAT (e.g., LTE or NR) and may include aresource pool within which UE 302 transmits the communication request.Additionally, the service announcement may include a specificdestination address for the UE (e.g., a Layer 2 destination address) ifthe destination address is different from the current address (e.g., theaddress of the streaming provider or UE transmitting the serviceannouncement). The service announcement may also include a network ortransport layer for UE 302 to transmit a communication request on. Forexample, the network layer (also referred to as “Layer 3” or “L3”) orthe transport layer (also referred to as “Layer 4” or “L4”) may indicatea port number of an application for the UE transmitting the serviceannouncement. In some cases, no IP addressing may be needed if thesignaling (e.g., PC5 signaling) carries a protocol (e.g., a real-timetransport protocol (RTP)) directly or gives a locally-generated randomprotocol. Additionally, the service announcement may include a type ofprotocol for credential establishment and QoS-related parameters.

After identifying a potential unicast connection target (UE 304 in theexample of FIG. 3 ), the initiating UE (UE 302 in the example of FIG. 3) may transmit a connection request 315 to the identified target UE 304.In some cases, the connection request 315 may be a first RRC messagetransmitted by UE 302 to request a unicast connection with UE 304 (e.g.,an RRCDirectConnectionSetupRequest message). For example, the unicastconnection may utilize the PC5 interface for the unicast link, and theconnection request 315 may be an RRC connection setup request message.Additionally, UE 302 may use a sidelink signaling radio bearer 305 totransport the connection request 315.

After receiving the connection request 315, UE 304 may determine whetherto accept or reject the connection request 315. UE 304 may base thisdetermination on a transmission/reception capability, an ability toaccommodate the unicast connection over the sidelink, a particularservice indicated for the unicast connection, the contents to betransmitted over the unicast connection, or a combination thereof. Forexample, if UE 302 wants to use a first RAT to transmit or receive data,but UE 304 does not support the first RAT, then UE 304 may reject theconnection request 315. Additionally or alternatively, UE 304 may rejectthe connection request 315 based on being unable to accommodate theunicast connection over the sidelink due to a limited radio resource, ascheduling issue, etc. Accordingly, UE 304 may transmit an indication ofwhether the request is accepted or rejected in a connection response320. Similar to UE 302 and the connection request 315, UE 304 may use asidelink signaling radio bearer 310 to transport the connection response320. Additionally, the connection response 320 may be a second RRCmessage transmitted by UE 304 in response to the connection request 315(e.g., an RRCDirectConnectionResponse message).

In some cases, sidelink signaling radio bearers 305 and 310 may be thesame sidelink radio signal bearer or may be separate sidelink signalingradio bearers. Accordingly, a radio link control (RLC) layeracknowledged mode (AM) may be used for sidelink signaling radio bearers305 and 310. A UE that supports the unicast connection may listen on alogical channel associated with the sidelink signaling radio bearers. Insome cases, the AS layer (i.e., Layer 2) may pass information directlythrough RRC signaling (e.g., control plane) instead of a V2X layer(e.g., data plane).

If the connection response 320 indicates that UE 304 accepted theconnection request 315, UE 302 may then transmit a connectionestablishment 325 message on the sidelink signaling radio bearer 305 toindicate that the unicast connection setup is complete. In some cases,the connection establishment 325 may be a third RRC message (e.g., anRRCDirectConnectionSetupComplete message). Each of the connectionrequest 315, the connection response 320, and the connectionestablishment 325 may use a basic capability when being transported fromone UE to the other UE to enable each UE to be able to receive anddecode the corresponding transmission (e.g., RRC message).

Additionally, identifiers may be used for each of the connection request315, the connection response 320, and the connection establishment 325(e.g., the RRC signaling). For example, the identifiers may indicatewhich UE 302/304 is transmitting which message and/or which UE 302/304the message is intended for. For physical (PHY) channels, the RRCsignaling and any subsequent data transmissions may use the sameidentifier (e.g., Layer 2 IDs). However, for logical channels, theidentifiers may be separate for the RRC signaling and for the datatransmissions. For example, on the logical channels, the RRC signalingand the data transmissions may be treated differently and have differentacknowledgement (ACK) feedback messaging. In some cases, for the RRCmessaging, a PHY layer ACK may be used for ensuring the correspondingmessages are transmitted and received properly.

One or more information elements may be included in the connectionrequest 315 and/or the connection response 320 for UE 302 and/or UE 304,respectively, to enable negotiation of corresponding AS layer parametersfor the unicast connection. For example, UE 302 and/or UE 304 mayinclude packet data convergence protocol (PDCP) parameters in acorresponding unicast connection setup message to set a PDCP context forthe unicast connection. In some cases, the PDCP context may indicatewhether or not PDCP duplication is utilized for the unicast connection.Additionally, UE 302 and/or UE 304 may include RLC parameters whenestablishing the unicast connection to set an RLC context of the unicastconnection. For example, the RLC context may indicate whether an AM(e.g., a reordering timer (t-reordering) is used) or an unacknowledgedmode (UM) is used for the RLC layer of the unicast communications.

Additionally, UE 302 and/or UE 304 may include medium access control(MAC) parameters to set a MAC context for the unicast connection. Insome cases, the MAC context may enable resource selection algorithms, ahybrid automatic repeat request (HARQ) feedback scheme (e.g., ACK ornegative ACK (NACK) feedback), parameters for the HARQ feedback scheme,carrier aggregation, or a combination thereof for the unicastconnection. Additionally, UE 302 and/or UE 304 may include PHY layerparameters when establishing the unicast connection to set a PHY layercontext for the unicast connection. For example, the PHY layer contextmay indicate a transmission format (unless transmission profiles areincluded for each UE 302/304) and a radio resource configuration (e.g.,bandwidth part (BWP), numerology, etc.) for the unicast connection.These information elements may be supported for different frequencyrange configurations (e.g., FR1 and FR2).

In some cases, a security context may also be set for the unicastconnection (e.g., after the connection establishment 325 message istransmitted). Before a security association (e.g., security context) isestablished between UE 302 and UE 304, the sidelink signaling radiobearers 305 and 310 may not be protected. After a security associationis established, the sidelink signaling radio bearers 305 and 310 may beprotected. Accordingly, the security context may enable secure datatransmissions over the unicast connection and the sidelink signalingradio bearers 305 and 310. Additionally, IP layer parameters (e.g.,link-local IPv4 or IPv6 addresses) may also be negotiated. In somecases, the IP layer parameters may be negotiated by an upper layercontrol protocol running after RRC signaling is established (e.g., theunicast connection is established). As noted above, UE 304 may base itsdecision on whether to accept or reject the connection request 315 on aparticular service indicated for the unicast connection and/or thecontents to be transmitted over the unicast connection (e.g., upperlayer information). The particular service and/or contents may be alsoindicated by an upper layer control protocol running after RRC signalingis established.

After the unicast connection is established, UE 302 and UE 304 maycommunicate using the unicast connection over a sidelink 330, wheresidelink data 335 is transmitted between the two UEs 302 and 304. Thesidelink 330 may correspond to sidelinks 162 and/or 168 in FIG. 1 and/orwireless unicast sidelink 242 in FIGS. 2A and 2B. In some cases, thesidelink data 335 may include RRC messages transmitted between the twoUEs 302 and 304. To maintain this unicast connection on sidelink 330, UE302 and/or UE 304 may transmit a keep alive message (e.g.,RRCDirectLinkAlive message, a fourth RRC message, etc.). In some cases,the keep alive message may be triggered periodically or on-demand (e.g.,event-triggered). Accordingly, the triggering and transmission of thekeep alive message may be invoked by UE 302 or by both UE 302 and UE304. Additionally or alternatively, a MAC control element (CE) (e.g.,defined over sidelink 330) may be used to monitor the status of theunicast connection on sidelink 330 and maintain the connection. When theunicast connection is no longer needed (e.g., UE 302 travels far enoughaway from UE 304), either UE 302 and/or UE 304 may start a releaseprocedure to drop the unicast connection over sidelink 330. Accordingly,subsequent RRC messages may not be transmitted between UE 302 and UE 304on the unicast connection.

FIG. 4 is a block diagram illustrating various components of anexemplary UE 400, according to aspects of the disclosure. In an aspect,the UE 400 may correspond to any of the UEs described herein. As aspecific example, the UE 400 may be a V-UE, such as V-UE 160 in FIG. 1 .For the sake of simplicity, the various features and functionsillustrated in the block diagram of FIG. 4 are connected together usinga common data bus that is meant to represent that these various featuresand functions are operatively coupled together. Those skilled in the artwill recognize that other connections, mechanisms, features, functions,or the like, may be provided and adapted as necessary to operativelycouple and configure an actual UE. Further, it is also recognized thatone or more of the features or functions illustrated in the example ofFIG. 4 may be further subdivided, or two or more of the features orfunctions illustrated in FIG. 4 may be combined.

The UE 400 may include at least one transceiver 404 connected to one ormore antennas 402 for communicating with other network nodes, such asV-UEs (e.g., V-UEs 160), infrastructure access points (e.g., roadsideaccess point 164), P-UEs (e.g., UEs 104), base stations (e.g., basestations 102), etc., via at least one designated RAT (e.g., C-V2X orIEEE 802.11p) over one or more communication links (e.g., communicationlinks 120, sidelinks 162, 166, 168, mmW communication link 184). Thetransceiver 404 may be variously configured for transmitting andencoding signals (e.g., messages, indications, information, and so on),and, conversely, for receiving and decoding signals (e.g., messages,indications, information, pilots, and so on) in accordance with thedesignated RAT.

As used herein, a “transceiver” may include at least one transmitter andat least one receiver in an integrated device (e.g., embodied as atransmitter circuit and a receiver circuit of a single communicationdevice) in some implementations, may comprise a separate transmitterdevice and a separate receiver device in some implementations, or may beembodied in other ways in other implementations. In an aspect, atransmitter may include or be coupled to a plurality of antennas (e.g.,antenna(s) 402), such as an antenna array, that permits the UE 400 toperform transmit “beamforming,” as described herein. Similarly, areceiver may include or be coupled to a plurality of antennas (e.g.,antenna(s) 402), such as an antenna array, that permits the UE 400 toperform receive beamforming, as described herein. In an aspect, thetransmitter(s) and receiver(s) may share the same plurality of antennas(e.g., antenna(s) 402), such that the UE 400 cannot simultaneouslyreceive or transmit at a given time. In some cases, a transceiver maynot provide both transmit and receive functionalities. For example, alow functionality receiver circuit may be employed in some designs toreduce costs when providing full communication is not necessary (e.g., areceiver chip or similar circuitry simply providing low-level sniffing).

The UE 400 may also include a satellite positioning service (SPS)receiver 406. The SPS receiver 406 may be connected to the one or moreantennas 402 for receiving satellite signals. The SPS receiver 406 maycomprise any suitable hardware and/or software for receiving andprocessing SPS signals, such as global positioning system (GPS) signals.The SPS receiver 406 requests information and operations as appropriatefrom the other systems, and performs the calculations necessary todetermine the UE’s 400 position using measurements obtained by anysuitable SPS algorithm.

One or more sensors 408 may be coupled to a processing system 410 toprovide information related to the state and/or environment of the UE400, such as speed, heading (e.g., compass heading), headlight status,gas mileage, etc. By way of example, the one or more sensors 408 mayinclude a speedometer, a tachometer, an accelerometer (e.g., amicroelectromechanical systems (MEMS) device), a gyroscope, ageomagnetic sensor (e.g., a compass), an altimeter (e.g., a barometricpressure altimeter), etc.

The processing system 410 may include one or more microprocessors,microcontrollers, ASICs, processing cores, digital signal processors, orthe like that provide processing functions, as well as other calculationand control functionality. The processing system 410 may include anyform of logic suitable for performing, or causing the components of theUE 400 to perform, at least the techniques provided herein.

The processing system 410 may also be coupled to a memory 414 forstoring data and software instructions for executing programmedfunctionality within the UE 400. The memory 414 may be on-board theprocessing system 410 (e.g., within the same integrated circuit (IC)package), and/or the memory 414 may be external to the processing system410 and functionally coupled over a data bus.

The UE 400 may include a user interface 450 that provides any suitableinterface systems, such as a microphone/speaker 452, keypad 454, anddisplay 456 that allow user interaction with the UE 400. Themicrophone/speaker 452 provides for voice communication services withthe UE 400. The keypad 454 comprises any suitable buttons for user inputto the UE 400. The display 456 comprises any suitable display, such as,for example, a backlit liquid crystal display (LCD), and may furtherinclude a touch screen display for additional user input modes.

In an aspect, the UE 400 may include a zone location component 470coupled to the processing system 410. The zone location component 470(which may correspond to zone location component 170 in FIG. 1 ) may bea hardware, software, or firmware component that, when executed, causesthe UE 400 to perform the operations described herein. For example, thezone location component 470 may be a software module stored in memory414 and executable by the processing system 410. As another example, thezone location component 470 may be a hardware circuit (e.g., an ASIC, anFPGA, etc.) within the UE 400.

In sidelink communications between two UEs (e.g., UE 302 and UE 304 inFIG. 3 ), the geographic location of the transmitter UE may be useful tothe receiver UE. For example, it may be useful for a receiver UE todetermine the distance between the two UEs when determining whether toprovide distance-based HARQ feedback to the transmitter UE.

In V2V communications, the concept of a geographic zone was introducedto facilitate the signaling of UE location. In zone-based positioning,the surface of the earth is partitioned into a plurality of zones basedon global navigation satellite system (GNSS) positioning. In anexemplary implementation, each zone has a size of 50-by-50 meters. Zonesmay be grouped into zone areas or other pluralities of zones. Forexample, a zone area may have a size of 32-by-32 zones. Each zone in azone area may be uniquely identifiable by a zone identifier (ID). Thus,for a 32-by-32 zone area (having 32*32=1024 zones), a zone ID may have avalue from 0 to 1023. In that case, a zone ID may be represented by 10bits (i.e., 2¹⁰=1024). Note that zones are used to indicate a UE’sposition because the signaling overhead (e.g., number of bits) needed totransmit the UE’s actual position (i.e., latitude, longitude, and/oraltitude) is not acceptable at lower layers.

An issue with zone-based positioning is that the zone indication maycause confusion at a receiver UE due to the wraparound of zone areas.That is, as discussed further below with reference to FIG. 5 , adjacentzone areas may reuse the same zone IDs. For example, if a zone ID isrepresented by 10 bits, allowing up to 1024 unique zone IDs, andadjacent zone areas include 1024 zones, each zone area will necessarilyhave to reuse the same 1024 zone IDs. This wraparound issue isespecially problematic when a receiver UE needs to determine thedistance to a transmitter UE based on the zone ID received from thetransmitter UE, but the receiver UE does not know to which zone area theindicated zone belongs.

FIG. 5 is a diagram 500 of an exemplary wraparound scenario, accordingto aspects of the disclosure. In the example of FIG. 5 , each of fourzone areas 510-1 to 510-4 (collectively, zone areas 510) has a size of8-by-8 (64) zones, meaning that a 6-bit zone ID value (i.e.,log2(8*8)=6, or 2⁶=8×8=64) is needed to uniquely identify a zone. Areceiver UE 504 is located in the black zone of zone area 510-3, andreceives a zone ID from a transmitter UE 502 that indicates thetransmitter UE’s 502 location. The indicated zone ID corresponds to eachof the shaded zones in the zone areas 510, due to the reuse of zone IDsacross zone areas. However, the receiver UE 504 may not know whether thetransmitter UE 502 is in the shaded zone within the same zone area asthe receiver UE 504 (i.e., zone area 510-3) or, due to wraparound,whether it is in the same zone (i.e., having the same zone ID) within anadjacent zone area (one of zone areas 510-1, 510-2, or 510-4). If thetransmitter UE’s 504 zone is used to determine the distance between thereceiver UE 504 and the transmitter UE 502, this uncertainty would makeit difficult, if not impossible, for the receiver UE 504 to calculatethat distance. As an example, when the distance is used by the receiverUE 504 to determine whether it needs to send HARQ feedback to thetransmitter UE 502 (e.g., where the receiver UE 504 is expected to sendthe HARQ feedback when the distance is less than a threshold), thereceiver UE 504 may make the wrong decision.

As will be appreciated, if UE 502 were to transmit both an identifier ofits zone area (i.e., zone area 510-3) and its zone ID within that zonearea, there would be no ambiguity regarding in which zone the UE 502 islocated. However, this approach would involve significant overhead, asit would necessitate transmitting both the zone ID and a secondidentifier for the zone area 510-3.

Accordingly, the present disclosure provides techniques to resolve theambiguity of reusing zone IDs across zone areas without specifying thezone area. These techniques enable a UE to indicate its location with azone ID but without changing the physical zone size or increasingsignaling overhead.

In an aspect, a zone area with a much larger size (e.g., 256-by-256zones) is configured at a transmitter UE. Each zone area should be largeenough that the wraparound issue would not affect a receiver UE’s HARQfeedback decision. That is, the zone area should be large enough that itwould be impossible for signals from more than one unique zone (i.e.,zones in different zone areas having the same zone ID) to reach thereceiver UE.

Each transmitter UE may have its own HARQ feedback distance requirement,based on, for example, distance requirements of a given application. Forexample, one application may have a 100 meter distance requirement,while another application may have a 500 meter distance requirement. Thetransmitter UE may signal a distance threshold D_(HARQ) based on thisdistance requirement, which is the minimum range to exclude HARQfeedback. That is, a receiver UE is expected to send HARQ feedback tothe transmitter UE if its distance from the transmitter UE is less thanD_(HARQ).

Adjacent zones in the large zone area may be grouped into zone groupshaving a group zone ID, as illustrated below in FIG. 6 . The zone ID ofan individual zone is referred to herein as a “first zone ID,” an“individual zone ID,” or simply a “zone ID,” and the ID of a group ofadjacent zones within a large zone area is referred to herein as a“second zone ID” or a “zone group ID.” As such, each zone may beidentified by a first zone ID unique to itself and a second zone ID thatit shares with one or more other adjacent zones of a group of zones.

FIG. 6 is a diagram 600 of a 16-by-16 zone area in which groups of fourzones are combined into zone groups and assigned second zone IDs,according to aspects of the disclosure. The number of zones that arecombined into a group of adjacent zones is based on the distancethreshold D_(HARQ). For example, the larger the value of D_(HARQ), themore zones there may be in a group of adjacent zones that share the samesecond zone ID. As a specific example, if each zone is 50-by-50 metersand D_(HARQ) is 100 meters, then, as illustrated in FIG. 6 , a group ofadjacent zones having the same second zone ID may comprise a group offour adjacent zones.

When transmitting its location to other UEs (e.g., in BSMs), atransmitter UE signals the second zone ID, rather than the first zoneID. This zone ID value may be indicated in lower layer signaling, suchas in sidelink control information (SCI). This means that the zone IDreceived at a receiver UE may correspond to multiple adjacent zones.Because multiple zones are combined into a group of adjacent zones, theaccuracy of the transmitter UE’s location may be degraded, andtherefore, the distance to the transmitter UE that the receiver UE isable to calculate may be similarly degraded. However, the locationaccuracy should still be sufficient enough for HARQ feedback distancedetermination purposes. For example, if each zone is 50-by-50 meters andD_(HARQ) is 100 meters, then a second zone ID corresponding to a groupof four zones (corresponding to a geographic area of 100-by-100 meters)is sufficient to determine whether the receiver UE is within 100 metersof the transmitter UE and should send HARQ feedback.

The above-disclosed technique has a number of benefits, includingreduced signaling overhead for the indication of the transmitter UE’slocation (i.e., the identifier of a group of adjacent zones in which thetransmitter UE is located, the second zone ID). As will be appreciated,the greater the value of D_(HARQ), the more adjacent zones that can begrouped together, and therefore, the fewer number of zone groups and thefewer number of bits needed for the second zone ID.

From the perspective of the transmitter UE, the transmitter UE firstdetermines its location (e.g., from GNSS). It then determines thecorresponding zone and first zone ID based on the determined GNSSlocation and one or more rules to form zones and first zone IDs. In anaspect, the mapping between a zone and a first zone ID may beone-to-one. That is, in a zone area, every zone has a unique first zoneID. A rule to form zones may be to partition the earth’s surface into aspecified number of zone areas, and to partition each zone area intowhatever number of zones of a specified size (e.g., 50-by-50 meters)will fit in the zone area. First zone IDs may be assigned to zones inthe zone area left to right and top to bottom, and each zone ID maycomprise the number of bits needed to uniquely identify each zone in thezone area (e.g., 10 bits for a zone area of 1024 zones).

Next, the transmitter UE determines a distance threshold for, forexample, HARQ feedback purposes. The transmitter UE then determines asecond zone ID based at least on one or more of the first zone ID, thedistance threshold, and the zone size. The transmitter UE transmits thesecond zone ID, rather than the first zone ID, and the distancethreshold to nearby receiver UE(s). The second zone ID and the distancethreshold may be transmitted in, for example, SCI.

In an aspect, the number of bits of the first zone ID may be n bits, andthe number of bits of the second zone ID may be m bits (where m is lessthan or equal to n). Further, n/2 bits may represent the x-axis of thefirst zone within a zone area or other plurality of zones, n/2 bits mayrepresent the y-axis of the first zone, m/2 bits may represent thex-axis of the second zone ID, and m/2 bits may represent a y-axis of thesecond zone ID. In an aspect, the second zone ID may be a subset of bitsof the first zone ID. In an aspect, the subset of bits of the first zoneID may represent one or more most significant bits of the first zone ID.

Referring to determining the second zone ID from the first zone ID ingreater detail, the number of adjacent zones (n_(zones)) that may sharethe same second zone ID may be based on the distance threshold(D_(HARQ)) and the zone size (L_(zone)). In principle, the larger thedistance threshold, the more adjacent zones that can share the samesecond zone ID. For example, when D_(HARQ) ≤ L_(zone), each zone (1²)has a unique zone ID. When L_(zone) < D_(HARQ) ≤ 2L_(zone), then everyfour (2²) zones share the same second zone ID. When 2L_(zone) < D_(HARQ)≤ 3L_(zone), then every nine (3²) zones share the same second zone ID,and so on. This principle can be abstracted as

$n_{\text{zones}} = \left( \left\lceil \frac{D_{\text{HARQ}}}{L_{\text{zone}}} \right\rceil \right)^{2}.$

As another example, when D_(HARQ) ≤ L_(zone), then each zone (1²) has aunique zone ID. When L_(zone) < D_(HARQ) ≤ 2L_(zone), then every four(2²) zones share the same zone ID. When 2L_(zone) < D_(HARQ) ≤4L_(zone), then every 16 (4²) zones share the same zone ID, and so on.This principle can be abstracted as

$n_{\text{zones}} = \left( 2^{\lceil{\log 2{(\frac{D_{\text{HARQ}}}{L_{\text{zone}}})}}\rceil} \right)^{2}.$

In this way, every n_(zones) adjacent zones are mapped to the samesecond zone ID.

The following is a detailed example. A first zone ID of N₁ = 16 bits canuniquely identify 2¹⁶ = 256 × 256 zones in a zone area. A second zone IDof N₂ = 10 bits can be carried by SCI (i.e., the second zone ID isexpressed by N₂ bits, and N₁ > N₂). It is determined (from D_(HARQ) andL_(zone)) that every four adjacent zones can share the same second zoneID (i.e., n_(zones) = 4, as illustrated in FIG. 6 ). For a first zone IDof bit length N₁ (i.e., 16 bits), the first

$\left( {\frac{N_{1}}{2} = n = 8} \right)$

bits can indicate the zone location along the X-axis, and the second

$\left( {\frac{N_{1}}{2} = n = 8} \right)$

bits can indicate the zone location along the Y-axis. Alternatively, thezones may simply be numbered from ‘1’ to ‘256.’ As such, each zone has aunique first zone ID in the zone area.

The second zone ID can be determined as follows. Assume the (decimal)value of the first

$\frac{N_{1}}{2}$

bits in the first zone ID is

M₁^(X),

and the (decimal) value of the second

$\frac{N_{1}}{2}$

bits in the first zone ID is

M₁^(Y).

The (decimal) value of the first

$\frac{N_{2}}{2} = e$

bits in the second zone ID is determined as

$M_{2}^{X} = {mod}\left( {\frac{M_{1}^{X}}{2^{\lceil{\log 2{(\frac{D_{\text{HARQ}}}{L_{\text{zone}}})}}\rceil}},2^{\frac{N_{2}}{2}}} \right),$

and the (decimal) value of the second

$\frac{N_{2}}{2} = e$

bits in the second zone ID is determined as

M₂^(Y)=

${mod}\left( {\frac{M_{1}^{Y}}{2^{\lceil{\log 2{(\frac{D_{\text{HARQ}}}{L_{\text{zone}}})}}\rceil}},2^{\frac{N_{2}}{2}}} \right).$

The effect of the above determination of the second zone ID isequivalent to every four zones sharing the same second zone ID, and theshared second zone ID being determined as the shared N₂ bits countingfrom the least significant bit (LSB) in the first zone IDs of the fourzones making up the group of adjacent zones.

For example, assume N₁=16 and N₂=10. For the first zone ID, this wouldresult in eight bits for the X-axis component and eight bits for theY-axis component. For the second zone ID, this would result in five bitsfor the X-axis component and five bits for the Y-axis component. Thefive bits may be the last five bits (i.e., the five LSBs) of the eightbits of the first zone ID if a zone group has one zone, or the five bitscounted from the second from the last bit of the eight bits of the firstzone ID if a zone group has four zones, or the five bits counted fromthe third from the last bit of the eight bits of the first zone ID if azone group has 16 zones. Thus, for example, if up to 10 bits are allowedfor the second zone ID, and a zone group has four zones, then some ofthe LSBs and some of the most significant bits (MSBs) from first zone IDwould be removed, and the remaining bits would be the second zone ID.However, if there is no constant number of bits constraint on the secondzone ID, then the second zone ID can be the MSBs of the first zone IDregardless of the number of MSBs.

FIG. 7 is a diagram 700 illustrating how to determine the bits of asecond zone ID 720 from the bits of a first zone ID 710, according toaspects of the disclosure. As illustrated in FIG. 7 , the first n bitsof the first zone ID 710 indicate the x-axis location of the zone withina zone area, and the second n bits of the first zone ID 710 indicate they-axis location of the zone within the zone area. As discussed above,the first half of the second zone ID 720 is mapped from part (e.g., thee LSBs) of the first half (i.e., the first n bits) of the first zone ID710. Likewise, the second half of the second zone ID 720 is mapped frompart (e.g., the e LSBs) of the second half (i.e., the second n bits) ofthe first zone ID 710.

From the perspective of the receiver UE, the receiver UE receives, froma transmitter UE, a second zone ID and a HARQ feedback distancethreshold. The receiver UE may determine the number of zones associatedwith the second zone ID based on the known size of a zone (e.g.,50-by-50 meters) and the HARQ feedback distance threshold. For example,if the HARQ feedback distance threshold is 100 meters, the receiver UEknows that there are four zones associated with the second zone ID. Thereceiver should know, or be able to determine, the location of the groupof zones sharing the second zone ID based on the second zone ID (e.g.,where the second zone ID indicates the x-y coordinates of the zonegroup) or by rule (e.g., where zone groups are numbered consecutivelyfrom top to bottom and left to right).

The receiver UE then determines the distance between itself and thetransmitter UE. More specifically, the receiver UE may determine thetransmitter UE’s location based on the second zone ID and the number ofzones in the zone group, which may be determined from the distancethreshold. The receiver UE may not need to recover the first zone IDfrom the second zone ID, but rather, can simply determine thetransmitter UE’s location as the location of the zones associated withthe second zone ID. The receiver UE’s location may be expressed by thezone ID in which it is located or its actual location (e.g., asdetermined by GNSS). The receiver UE then transmits HARQ feedback to thetransmitter UE if the determined distance is smaller than the receivedHARQ feedback distance threshold.

FIG. 8 illustrates an exemplary call flow 800 between a transmitter UE802 and one or more receiver UEs 804, according to aspects of thedisclosure. UEs 802 and 804 may correspond to any of the UEs describedherein. As a specific example, UEs 802 and 804 may be V-UEs.

At 810, the transmitter UE 802 transmits a second zone ID and a distancethreshold (e.g., a HARQ feedback distance threshold) to the one or morereceiver UEs 804. The second zone ID and the distance threshold may beincluded in a BSM broadcasted by the transmitter UE 802.

At 820, the one or more receiver UEs 804 determine the distance betweenthemselves and the transmitter UE is less than the distance thresholdbased on the second zone ID and the location of the respective receiverUE(s), and optionally, the zone size.

At 830, the one or more receiver UEs 804 transmit a feedback message(e.g., a HARQ feedback message) to the transmitter UE.

FIG. 9 illustrates a method 900 for wireless communication, according toaspects of the disclosure. The method 900 may be performed by atransmitter UE (e.g., any of the UEs described herein).

At 910, the transmitter UE determines a first zone ID corresponding to afirst zone in which the transmitter UE is located. The first zone ID maybe the x-y coordinates of the first zone within, for example, a zonearea, a set of zones, or some plurality of zones, such as the first zoneID 710 in FIG. 7 . In an aspect, operation 910 may be performed bytransceiver 404, processing system 410, memory 414, and/or zone locationcomponent 470, any or all of which may be considered means forperforming this operation.

At 920, the transmitter UE determines a distance threshold based on adistance requirement of an application (e.g., a navigation application,an autonomous driving application, or the like) associated with thetransmitter UE. Alternatively, the distance requirement and/or distancethreshold may be specified in the applicable standard. In an aspect,operation 920 may be performed by transceiver 404, processing system410, memory 414, and/or zone location component 470, any or all of whichmay be considered means for performing this operation.

At 930, the transmitter UE determines a second zone ID (e.g., secondzone ID 720 in FIG. 7 ) based on the first zone ID, the distancethreshold, a size of the first zone, or any combination thereof. Forexample, the transmitter UE may determine the second zone ID asdescribed with reference to FIG. 7 . In an aspect, operation 930 may beperformed by transceiver 404, processing system 410, memory 414, and/orzone location component 470, any or all of which may be considered meansfor performing this operation.

At 940, the transmitter UE transmits the second zone ID and the distancethreshold to one or more receiver UEs, as at 810 of FIG. 8 . In anaspect, the distance threshold may not be necessary if, for example, itis specified in the applicable standard. In an aspect, operation 940 maybe performed by transceiver 404, processing system 410, memory 414,and/or zone location component 470, any or all of which may beconsidered means for performing this operation.

FIG. 10 illustrates a method 1000 for wireless communication, accordingto aspects of the disclosure. The method 1000 may be performed by areceiver UE (e.g., any of the UEs described herein).

At 1010, the receiver UE receives, from a transmitter UE, a second zoneID and a distance threshold. In an aspect, operation 1010 may beperformed by transceiver 404, processing system 410, memory 414, and/orzone location component 470, any or all of which may be considered meansfor performing this operation.

At 1020, the receiver UE determines a location of the receiver UE. In anaspect, operation 1020 may be performed by transceiver 404, processingsystem 410, memory 414, and/or zone location component 470, any or allof which may be considered means for performing this operation.

At 1030, the receiver UE determines a distance between the receiver UEand the transmitter UE based on the second zone ID and the location ofthe receiver UE. In an aspect, operation 1030 may be performed bytransceiver 404, processing system 410, memory 414, and/or zone locationcomponent 470, any or all of which may be considered means forperforming this operation.

At 1040, the receiver UE transmits, based on the distance between thereceiver UE and the transmitter UE being less than the distancethreshold, a feedback message to the transmitter UE. In an aspect,operation 1040 may be performed by transceiver 404, processing system410, memory 414, and/or zone location component 470, any or all of whichmay be considered means for performing this operation.

Those of skill in the art will appreciate that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Further, those of skill in the art will appreciate that the variousillustrative logical blocks, modules, circuits, and algorithm stepsdescribed in connection with the aspects disclosed herein may beimplemented as electronic hardware, computer software, or combinationsof both. To clearly illustrate this interchangeability of hardware andsoftware, various illustrative components, blocks, modules, circuits,and steps have been described above generally in terms of theirfunctionality. Whether such functionality is implemented as hardware orsoftware depends upon the particular application and design constraintsimposed on the overall system. Skilled artisans may implement thedescribed functionality in varying ways for each particular application,but such implementation decisions should not be interpreted as causing adeparture from the scope of the present disclosure.

The various illustrative logical blocks, modules, and circuits describedin connection with the aspects disclosed herein may be implemented orperformed with a general purpose processor, a DSP, an ASIC, an FPGA, orother programmable logic device, discrete gate or transistor logic,discrete hardware components, or any combination thereof designed toperform the functions described herein. A general purpose processor maybe a microprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aprocessor may also be implemented as a combination of computing devices,e.g., a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration.

The methods, sequences and/or algorithms described in connection withthe aspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module may reside in random access memory (RAM), flashmemory, read-only memory (ROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), registers, hard disk, aremovable disk, a CD-ROM, or any other form of storage medium known inthe art. An exemplary storage medium is coupled to the processor suchthat the processor can read information from, and write information to,the storage medium. In the alternative, the storage medium may beintegral to the processor. The processor and the storage medium mayreside in an ASIC. The ASIC may reside in a user terminal (e.g., UE). Inthe alternative, the processor and the storage medium may reside asdiscrete components in a user terminal.

In one or more exemplary aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another. Astorage media may be any available media that can be accessed by acomputer. By way of example, and not limitation, such computer-readablemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage or other magnetic storage devices, or anyother medium that can be used to carry or store desired program code inthe form of instructions or data structures and that can be accessed bya computer. Also, any connection is properly termed a computer-readablemedium. For example, if the software is transmitted from a website,server, or other remote source using a coaxial cable, fiber optic cable,twisted pair, digital subscriber line (DSL), or wireless technologiessuch as infrared, radio, and microwave, then the coaxial cable, fiberoptic cable, twisted pair, DSL, or wireless technologies such asinfrared, radio, and microwave are included in the definition of medium.Disk and disc, as used herein, includes compact disc (CD), laser disc,optical disc, digital versatile disc (DVD), floppy disk and Blu-ray discwhere disks usually reproduce data magnetically, while discs reproducedata optically with lasers. Combinations of the above should also beincluded within the scope of computer-readable media.

While the foregoing disclosure shows illustrative aspects of thedisclosure, it should be noted that various changes and modificationscould be made herein without departing from the scope of the disclosureas defined by the appended claims. The functions, steps and/or actionsof the method claims in accordance with the aspects of the disclosuredescribed herein need not be performed in any particular order.Furthermore, although elements of the disclosure may be described orclaimed in the singular, the plural is contemplated unless limitation tothe singular is explicitly stated.

What is claimed is:
 1. A method for wireless communication performed ata receiver user equipment (UE), comprising: receiving, from atransmitter UE, a second zone identifier (ID) and a distance threshold;determining a location of the receiver UE; determining a distancebetween the receiver UE and the transmitter UE based on the second zoneID and the location of the receiver UE, wherein the second zone ID isthe same for each of a subset of adjacent zones of a set of zones,wherein a first zone ID represents an individual zone within the subsetof adjacent zones, and wherein a number of bits of the first zone ID isn bits, a number of bits of the second zone ID is m bits, and m is lessthan n; and transmitting, based on the distance between the receiver UEand the transmitter UE being less than the distance threshold, afeedback message to the transmitter UE.
 2. The method of claim 1,wherein the set of zones comprises a zone area or a plurality of zones.3. The method of claim 1, wherein: a surface area of the earth isdivided into a plurality of zone areas, the plurality of zone areasincluding a first zone area, the first zone area comprises a pluralityof zones, the plurality of zones is uniquely identified within the firstzone area by a corresponding plurality of zone IDs, the plurality ofzone IDs including the first zone ID, and a group of adjacent zoneswithin the plurality of zones is associated with the second zone ID. 4.The method of claim 1, wherein: a surface area of the earth is dividedinto a plurality of zones, the plurality of zones including a firstzone, the plurality of zones is uniquely identified within the pluralityof zones by a corresponding plurality of zone IDs, the plurality of zoneIDs including the first zone ID, and a group of adjacent zones withinthe plurality of zones is associated with the second zone ID, the groupof adjacent zones including the first zone.
 5. The method of claim 1,wherein: n/2 bits represent an x-axis of the first zone, n/2 bitsrepresent a y-axis of the first zone, m/2 bits represent an x-axis ofthe second zone ID, and m/2 bits represent a y-axis of the second zoneID.
 6. The method of claim 1, wherein the second zone ID comprises asubset of bits of the first zone ID.
 7. The method of claim 6, whereinthe subset of bits of the first zone ID comprises one or more mostsignificant bits of the first zone ID.
 8. The method of claim 1, whereinthe determining the distance comprises: determining a location of thetransmitter UE based on the second zone ID, a size of a zone, and thedistance threshold; and determining the distance between the receiver UEand the transmitter UE based on the location of the transmitter UE andthe location of the receiver UE.
 9. The method of claim 1, wherein thelocation of the receiver UE is determined based on signals from a globalnavigation satellite system (GNSS).
 10. The method of claim 1, whereinthe distance threshold is a hybrid automatic repeat request (HARQ)feedback distance threshold.
 11. The method of claim 10, wherein thefeedback message comprises a HARQ feedback message.
 12. The method ofclaim 1, wherein the receiver UE receives the second zone ID and thedistance threshold over a sidelink communication link.
 13. The method ofclaim 12, wherein the receiver UE receives the second zone ID and thedistance threshold over the sidelink communication link in sidelinkcontrol information.
 14. A receiver user equipment (UE), comprising: amemory; at least one transceiver; and at least one processor coupled tothe memory and the at least one transceiver, the at least one processorconfigured to: receive, from a transmitter UE via the at least onetransceiver, a second zone identifier (ID) and a distance threshold;determine a location of the receiver UE; determine a distance betweenthe receiver UE and the transmitter UE based on the second zone ID andthe location of the receiver UE, wherein the second zone ID is the samefor each of a subset of adjacent zones of a set of zones, wherein afirst zone ID represents an individual zone within the subset ofadjacent zones, and wherein a number of bits of the first zone ID is nbits, a number of bits of the second zone ID is m bits, and m is lessthan n; and transmit, via the at least one transceiver, based on thedistance between the receiver UE and the transmitter UE being less thanthe distance threshold, a feedback message to the transmitter UE. 15.The receiver UE of claim 14, wherein the set of zones comprises a zonearea or a plurality of zones.
 16. The receiver UE of claim 14, wherein:a surface area of the earth is divided into a plurality of zone areas,the plurality of zone areas including a first zone area, the first zonearea comprises a plurality of zones, the plurality of zones is uniquelyidentified within the first zone area by a corresponding plurality ofzone IDs, the plurality of zone IDs including the first zone ID, and agroup of adjacent zones within the plurality of zones is associated withthe second zone ID.
 17. The receiver UE of claim 14, wherein: a surfacearea of the earth is divided into a plurality of zones, the plurality ofzones including a first zone, the plurality of zones is uniquelyidentified within the plurality of zones by a corresponding plurality ofzone IDs, the plurality of zone IDs including the first zone ID, and agroup of adjacent zones within the plurality of zones is associated withthe second zone ID, the group of adjacent zones including the firstzone.
 18. The receiver UE of claim 14, wherein: n/2 bits represent anx-axis of the first zone, n/2 bits represent a y-axis of the first zone,m/2 bits represent an x-axis of the second zone ID, and m/2 bitsrepresent a y-axis of the second zone ID.
 19. The receiver UE of claim14, wherein the second zone ID comprises a subset of bits of the firstzone ID.
 20. The receiver UE of claim 19, wherein the subset of bits ofthe first zone ID comprises one or more most significant bits of thefirst zone ID.
 21. The receiver UE of claim 14, wherein the at least oneprocessor configured to determine the distance comprises the at leastone processor configured to: determine a location of the transmitter UEbased on the second zone ID, a size of a zone, and the distancethreshold; and determine the distance between the receiver UE and thetransmitter UE based on the location of the transmitter UE and thelocation of the receiver UE.
 22. The receiver UE of claim 14, whereinthe location of the receiver UE is determined based on signals from aglobal navigation satellite system (GNSS).
 23. The receiver UE of claim14, wherein the distance threshold is a hybrid automatic repeat request(HARQ) feedback distance threshold.
 24. The receiver UE of claim 23,wherein the feedback message comprises a HARQ feedback message.
 25. Thereceiver UE of claim 14, wherein the receiver UE receives the secondzone ID and the distance threshold over a sidelink communication link.26. The receiver UE of claim 25, wherein the receiver UE receives thesecond zone ID and the distance threshold over the sidelinkcommunication link in sidelink control information.
 27. A receiver userequipment (UE), comprising: means for receiving, from a transmitter UE,a second zone identifier (ID) and a distance threshold; means fordetermining a location of the receiver UE; means for determining adistance between the receiver UE and the transmitter UE based on thesecond zone ID and the location of the receiver UE, wherein the secondzone ID is the same for each of a subset of adjacent zones of a set ofzones, wherein a first zone ID represents an individual zone within thesubset of adjacent zones, and wherein a number of bits of the first zoneID is n bits, a number of bits of the second zone ID is m bits, and m isless than n; and means for transmitting, based on the distance betweenthe receiver UE and the transmitter UE being less than the distancethreshold, a feedback message to the transmitter UE.
 28. Anon-transitory computer-readable medium storing computer-executableinstructions that, when executed by a receiver user equipment (UE),cause the receiver UE to: receive, from a transmitter UE, a second zoneidentifier (ID) and a distance threshold; determine a location of thereceiver UE; determine a distance between the receiver UE and thetransmitter UE based on the second zone ID and the location of thereceiver UE, wherein the second zone ID is the same for each of a subsetof adjacent zones of a set of zones, wherein a first zone ID representsan individual zone within the subset of adjacent zones, and wherein anumber of bits of the first zone ID is n bits, a number of bits of thesecond zone ID is m bits, and m is less than n; and transmit, based onthe distance between the receiver UE and the transmitter UE being lessthan the distance threshold, a feedback message to the transmitter UE.